Gathered sources creating a RPi headless bluetooth receiver that auto connects at boot to my specific phone's MAC address
Sources: https://gist.github.com/mill1000/74c7473ee3b4a5b13f6325e9994ff84c https://www.raspberrypi.org/forums/viewtopic.php?t=170353
https://www.max2play.com/en/forums/topic/pi3-bluetooth-auto-reconnect-option-script/ - reconnect?
https://retropie.org.uk/forum/topic/1754/help-with-script-to-maintain-bluetooth-connection/10 - Reconnect?
I found my solution. I made the following changes (in bold) to my /bin/connect-bluetooth.sh file.
#!/bin/bash
while (sleep 30)
do
sudo bluetoothctl << EOF
power on
connect [MAC Address]
exit
EOF
done
You can change the sleep value to whatever you'd prefer. 30 seconds seemed to work out fine for me. If i start to get impatient, I'll change it down to 15.
https://raspberrypi.stackexchange.com/questions/53408/automatically-connect-trusted-bluetooth-speaker - Script to place your known BT devices to auto connect. Maybe add two+ mac addresses and then create logic to try for duration, then next...
This gist will show how to setup Raspbian Stretch as a headless Bluetooth A2DP audio sink. This will allow your phone, laptop or other Bluetooth device to play audio wirelessly through a Rasperry Pi.
A quick search will turn up a plethora of tutorials on setting up A2DP on the Raspberry Pi. However, I felt this gist was necessary because this solution is:
- Automatic & Headless - Once setup, the system is entirely automatic. No user iteration is required to pair, connect or start playback. Therefore the Raspberry Pi can be run headless.
- Simple - This solution has few dependencies, readily available packages and minimal configuration.
- Up to date - As of December 2017. Written for Raspbian Stretch & Bluez 5.43
- Raspbian Stretch - I used the Lite version as this is a headless setup. See the official guide if you need help.
- Bluez-alsa - Available in the Raspbian package repo. This software allows us to stream A2DP audio over Bluetooth without PulseAudio.
- Raspberry Pi with Bluetooth - The Raspberry Pi 3 has integrated Bluetooth, however there is a known bug when the WiFi is used simultaneously. Cheap USB Bluetooth dongles work equally well.
My Personal Experience:
- Avoid integrated Bluetooth - I used the RPi Zero W's onboard bluetooth and had issues with the the RPi0W initiate the connection on boot startup. With the integrated Bluetooth, The phone and RPi0W would never autoconnect on boot, but my RPi1 did. Everytime. Checked code, it was the same. I was using a USB Bluetooth dongle. I had used an RPi 1 and had everthing working, but the audio was poor and I needed cleaner high end(Was distorted and gross sounding). I ended up getting RPi0W with HIFIBerry DAC Zero for size reasons. My RPi0W was working fine, but I could hear some RF noise occur every 4-6 seconds. If it was plugged into a USB phone car charger the noise was unbearable, which was due to grounding issue. I purchased a Ground Loop Isolator and it helped dramatically with all ground noise.
I thought that the noise was caused by WIFI being enabled, So I modified the script that provides monitoring and running of autoconnect script to enable and disable wlan0(integrated Wifi) on reboot. If a bluetooth device connects, disable wifi on next boot. If no bluetooth device connects within 2 mins, delete line in /boot/config.txt that disables wifi on boot, which in turn enables wlan0 as well as brings me access to SSH.
If you are using a separate USB Bluetooth dongle, disable the integrated Bluetooth to prevent conflicts.
To disable the integrated Bluetooth add the following
# Disable onboard Bluetooth
dtoverlay=pi3-disable-bt
to /boot/config.txt and execute the following command
sudo systemctl disable hciuart.service
If you have higher quality DAC then make sure it is configured correctly. If using 3.5mm jack on RPi(Non Zero/W) ensure that the audio is outputting to the jack and not HDMI out.
I have a HIFIBerry DAC Zero follow steps: https://www.hifiberry.com/build/documentation/configuring-linux-3-18-x/
Go and edit the file /boot/config.txt
remove or comment out the line
dtparam=audio=on
and place the line configuring the HIFIBerry
dtoverlay=hifiberry-dac
First make sure the system is up to date using the following commands.
sudo apt-get update
sudo apt-get upgrade
Then reboot the Pi to ensure the latest kernel is loaded.
Now install the required packages.
sudo apt-get install bluealsa python-dbus
Normally a Bluetooth device is only discoverable for a limited amount of time. Since this is a headless setup we want the device to always be discoverable.
- Set the DiscoverableTimeout in
/etc/bluetooth/main.confto 0
# How long to stay in discoverable mode before going back to non-discoverable
# The value is in seconds. Default is 180, i.e. 3 minutes.
# 0 = disable timer, i.e. stay discoverable forever
DiscoverableTimeout = 0
- Enable discovery on the Bluetooth controller
sudo bluetoothctl
power on
discoverable on
exit
- Change RPi Bluetooth name
sudo bluetoothctl
system-alias YourBluetoothDeviceName
exit
Change "YourBluetoothDeviceName" to What you want the device to be called/broadcast as.
https://gist.github.com/mill1000/74c7473ee3b4a5b13f6325e9994ff84chttps://gist.github.com/mill1000/74c7473ee3b4a5b13f6325e9994ff84c A Bluetooth agent is a piece of software that handles pairing and authorization of Bluetooth devices. The following agent allows the Raspberry Pi to automatically pair and accept A2DP connections from Bluetooth devices. All other Bluetooth services are rejected.
Copy the included file a2dp-agent to /usr/local/bin and make the file executable with
sudo chmod +x /usr/local/bin/a2dp-agent
Before continuing, verify that the agent is functional. The Raspberry Pi should be discoverable, pairable and recognized as an audio device.
Note: At this point the device will not output any audio. This step is only to verify the Bluetooth is discoverable and bindable.
- Manually run the agent by executing
sudo /usr/local/bin/a2dp-agent
- Attempt to pair and connect with the Raspberry Pi using your phone or computer.
- The agent should output the accepted and rejected Bluetooth UUIDs
A2DP Agent Registered
AuthorizeService (/org/bluez/hci0/dev_94_01_C2_47_01_AA, 0000111E-0000-1000-8000-00805F9B34FB)
Rejecting non-A2DP Service
AuthorizeService (/org/bluez/hci0/dev_94_01_C2_47_01_AA, 0000110d-0000-1000-8000-00805f9b34fb)
Authorized A2DP Service
AuthorizeService (/org/bluez/hci0/dev_94_01_C2_47_01_AA, 0000111E-0000-1000-8000-00805F9B34FB)
Rejecting non-A2DP Service
If the Raspberry Pi is not recognized as a audio device, ensure that the bluealsa package was installed as part of the Initial Setup
I had an issue with the RPI pairing and then just disconnecting. It would no longer appear as if it were connected, but it would stay in the paired(saved) devices section in my phone Bluetooth connected devices. Antannah(From mill1000 Guide's comments) managed to fix this by adding the a2dp-sink as protocol.
I had to to add to /lib/systemd/system/bluealsa.service
and add this line -p a2dp-sink
by changing the ExecStart line to
ExecStart=/usr/bin/bluealsa -p a2dp-sink.
Also, try changing the user stated there is User=root to User=pi or vice versa. (Might be referring to one of the files below that this helps with troubleshooting step?)
To make the A2DP Bluetooth Agent run on boot copy the included file bt-agent-a2dp.service to /etc/systemd/system.
Now run the following command to enable the A2DP Agent service
sudo systemctl enable bt-agent-a2dp.service
Bluetooth devices should now be able to discover, pair and connect to the Raspberry Pi without any user intervention.
Now that Bluetooth devices can pair and connect with the Raspberry Pi we can test the audio playback.
The tool bluealsa-aplay is used to forward audio from the Bluetooth device to the ALSA output device (sound card).
Execute the following command to accept A2DP audio from any connected Bluetooth device.
bluealsa-aplay -vv 00:00:00:00:00:00
Play a song on the Bluetooth device and the Raspberry Pi should output audio on either the headphone jack or the HDMI port. See this guide for configuring the audio output device of the Raspberry Pi.
To make the audio playback run on boot copy the included file a2dp-playback.service to /etc/systemd/system.
Now run the following command to enable A2DP Playback service
sudo systemctl enable a2dp-playback.service
Reboot and enjoy!
I have to run the volume on my phone at 66% in order to prevent distortion. It has to do with the max output of the HIFIBerry and it reaches an old standard for HIFI of 2Vdmfs or something, while the normal is only 1vdmfs. ----- Correct this
If you are experiencing low volume output, run alsamixer and increase the volume of the Pi's soundcard.
I needed Wifi to SSH in to modify any settings/files I wanted to create some logic to turn off Wifi and disable DHCPCD on boot up. Possibly eliminating interference with Bluetooth dongle and hopefully reducing boot time to get auto-connected faster. If a bluetooth device connects, It will run DisableWifiOnBoot disabling Wifi and DHCPCD on boot up. This perpetuates a fast boot up and will assume its existence as Headless Bluetooth Receiver mode. If there is no bluetooth connection within certain timeframe (adjustable by numloop threshold) EnableWifiOnBoot script will run and enable Wifi and DHCPCD service on boot. Now if you connect after the numloop threshold, you will then trigger DisableWifiOnBoot. If you need to configure the RPi Zero W then just turn off Bluetooth on your phone or device that it will auto-connect to boot it up. Watch the clock to ensure you have let the script re-enable the Wifi by running EnableWifiOnBoot and then unplug and re-plug the RPi and it will boot with the ability to SSH.
Use this command to find out which eventX number your Bluetooth will connect under and make sure it matches the the code below. Or disable the HDMI or which ever device is event0
cat /proc/bus/input/devices | grep -P '^[NH]: ' | paste - -
OK! We need to enter over into the Python world. Jason Woodruff(https://raspberrypi.stackexchange.com/users/48183/jason-woodruff) wrote a Python program that will watch for the bluetooth device. In short, it will activate the connection between RPi and your bluetooth speaker, once your bluetooth speaker is turned on. And vice versa. Let's create a directory called python in your home directory To do that, type this:
mkdir -p ~/python
Now let's create the python program file. To do that, type this:
I created two bash files that have mine and my wife's MAC address with a script to initiate a connect with bluetoothctl. I drive the car the most so I am first and then it will try the Wife's phone. Works well!
If you do not need this or want to disable autoconnect, just remove these lines from on.py
if numloop % 2 == 0:
print('Attempting to Pair to Phone 1')
subprocess.call('sudo /home/pi/scripts/autopair', shell=True)
else:
print('Attempting to Pair to Phone 2')
subprocess.call('sudo /home/pi/scripts/autopair2', shell=True)
Using the on.py file I modified it to my use case
#!/usr/bin/python
#
# Monitor removal of bluetooth reciever
import os
import sys
import subprocess
import time
btconn = False # used to monitor if Bluetooth connection is triggered
def blue_it():
global btconn
global connnumloop
status = subprocess.call('ls /dev/input/event0 2>/dev/null', shell=True)
connnumloop = 0
while status == 0:
print("Bluetooth UP")
print(status)
status = subprocess.call('ls /dev/input/event0 2>/dev/null', shell=True)
time.sleep(1)
if status == 0:
if connnumloop == 0:
btconn = True
subprocess.call('sudo /home/pi/scripts/DisableWifiOnBoot', shell=True)
print("Wifi disabled for next boot")
print("BT Device has connected since boot: {}".format(btconn))
connnumloop += 1
time.sleep(29)
else:
waiting()
def waiting():
global btconn
global numloop
status = subprocess.call('ls /dev/input/event0 2>/dev/null', shell=True)
numloop = 0
while status == 2:
print("Bluetooth DOWN")
print(status)
if numloop % 2 == 0:
print('Attempting to Pair to Phone 1')
subprocess.call('sudo /home/pi/scripts/autopair', shell=True)
else:
print('Attempting to Pair to Phone 2')
subprocess.call('sudo /home/pi/scripts/autopair2', shell=True)
time.sleep(1)
if btconn == False:
if numloop == 2:
subprocess.call('sudo /home/pi/scripts/EnableWifiOnBoot', shell=True)
time.sleep(1)
print("Wifi enabled for next boot")
time.sleep(13)
status = subprocess.call('ls /dev/input/event0 2>/dev/null', shell=True)
numloop += 1
print("Loop count: {} | BT Device has connected since boot: {}".format(numloop,btconn))
else:
blue_it()
blue_it()
Now press CTRL + x and then press Enter to save the Python program file. Now we need to make this file executable. To do that, type this:
chmod +x ~/python/on.py
go to:
nano ~/.bashrc
and place the code:
wait
~/python/on.py
I tried this option of using sed but it ended up clearing out /boot/config.txt file completely rendering the unit useless. I therefore went the route of just copying a properly configured config.txt.bak file to replace existing one. It works flawlessly.
add this to file DisableWifiOnBoot
~/scripts/
#!/bin/bash
# DisableWifiOnBoot Script
# Run on BT Device Connect
# Check if line written
grep -q "dtoverlay=pi3-disable-wifi" /boot/config.txt
if [[ $(echo $?) == 1 ]];
then
echo "Line not in /boot/config.txt"
# Write Line
sudo sed '/#_Disable_Onboard_WIFI/ a dtoverlay=pi3-disable-wifi' -i /boot/config.txt;echo $?
echo "Writing line to disable WIFI on boot"
else
echo "Line exists already, WIFI will be disabled on boot"
fi
echo "Done Disabling Wifi On Next Boot"
#Disable DHCPCD on next boot in hopes of speeding up boot time
sudo update-rc.d -f dhcpcd remove
next we need to add a line to the /boot/config.txt at the end of the file. This is where we will place the enabling and disabling line with the two scripts.
#_Disable_Onboard_WIFI
make it executable
sudo chmod +x ~/scripts/DisableWifiOnBoot
#!/bin/bash
# EnableWifiOnBoot Script
# Clear out line disabling WIFI on boot
# Check if line written
grep -q "dtoverlay=pi3-disable-wifi" /boot/config.txt
if [[ $(echo $?) == 0 ]]; then
echo "Line is within /boot/config.txt"
# Write Line
sudo sed -e s/dtoverlay=pi3-disable-wifi//g -i /boot/config.txt;echo $?
else
echo "Line is not in file, Wifi will be enabled on next boot"
fi
echo "Done Enabling Wifi on Next Boot"
#Re-enable DHCPCD on next boot in hopes of speeding up boot time
sudo update-rc.d dhcpcd defaults
make it executable
sudo chmod +x ~/scripts/EnableWifiOnBoot
Inspired by other Car's bluetooth systems that resume playing where you left off, I was on a mission to get this implemented. Turns out it was easy enough as the A2DP-Agent sets up the Bluetooth AVRCP(Audio/Video Remote Control Protocol) profile needed to transmit those messages. Its a matter of setting up the command and adding it into the Python script.
installing the qdbus on the rpi, you can communicate commands with the Mac address formatted below
qdbus --system org.bluez /org/bluez/hci0/dev_00_00_00_00_00_00/player0 org.bluez.MediaPlayer1.Play